Global Biomass of Wild versus Domestic Mammals
The total mass of wild terrestrial and marine mammals remains far smaller than the combined weight of domesticated animals such as cattle, pigs, and sheep, along with other farmed species. This conclusion comes from the first comprehensive census of wild mammalian biomass. Researchers estimate cattle and related livestock at about 630 million tons, a figure roughly 30 times greater than the biomass of all wild land mammals and about 15 times the biomass of wild marine mammals. The study appears in the Proceedings of the National Academy of Sciences and highlights how human activity has reshaped the earth’s mammalian balance for readers in Canada, the United States, and beyond. study
Earlier findings published in Nature, followed by discussion from the same team, indicated that by 2020 the mass of human-made objects—from skyscrapers to newspapers—already exceeded every other form of biomass on Earth, from sequoias to bees. The latest work offers a new angle on human influence, measured by the ratio of people and livestock to wild mammals, underscoring the broader ecological footprint of human society. collaboration
Illustrations show the proportion of different mammals on the planet as described in the PNAS report. figures
“This work aims to capture the bigger picture,” explained a lead researcher. “The stunning diversity of mammal species can obscure the rapid changes our planet is undergoing. Yet the global distribution of biomass provides tangible evidence that humanity and domestic livestock dominate the remaining populations of wild mammals.”
To estimate the biomass of warm-blooded mammals, researchers compiled up-to-date censuses of wild species and key traits across hundreds of species. The study was led by principal investigators who transformed extensive data into biomass estimates, creating a robust cross-continental framework for comparison across ecosystems. lab report
About half of the global mammalian biomass came directly from these censuses. The other half was projected using a machine learning model trained on the initial data, incorporating factors such as body weight, regional distribution, diet, and zoological classification. The resulting analyses provide a clearer picture of where wild mammals stand in the planetary biomass ledger. notes
The research also highlights how human activity has affected still-wild populations. Several large mammals that top biomass charts, including white-tailed deer and wild boar, owe much of their abundance to human influence and are considered pests in some regions. This dynamic underscores the need for careful monitoring of wild populations as ecosystems respond to anthropogenic pressures. assessment
These biomass estimates offer a framework for tracking wild mammal populations globally and assessing potential disease risks that could travel from wild animals to humans. Epidemiologists caution that this evolving balance may continue to shape patterns of disease emergence among people and animals alike. review
Only 2.5 Kilograms of Wild Mammals Per Person
In efforts to understand the human footprint, researchers in the same lab are tracking how mammalian biomass has shifted over the past century. One researcher noted that it is important to know precisely when the total weight of domesticated mammals surpasses that of wild ones. A clear grasp of these changes can help set conservation goals and offer insight into long-term global processes. briefing
Much of the public’s connection with nature comes through media, museums, and ecotourism, which shapes how people view the natural world. In reality, the weight of all remaining wild land mammals is less than 10 percent of humanity’s total weight, roughly 2.5 kilograms of wild land mammals per person. This quantification helps illustrate the magnitude of human impact and informs expectations about nature’s future under ongoing human influence. outreach
Evidence for these conclusions comes from ongoing biomass analyses conducted within the research program. The work highlights the value of publicly available census data and robust modeling to generate a comprehensive snapshot of global biomass distribution. The findings reflect collaborative efforts across ecological measurement and data analysis teams to build a coherent, data-driven view of mammal biomass worldwide. synthesis
Citation indicates that the results originate from a collaboration within a major science institute’s environmental sciences program, with ongoing cooperation across teams focused on ecological measurements and data modeling. This synthesis strengthens the understanding of how domesticated animals compare to wild populations and informs policy directions for conservation and ecosystem management. Acknowledgment is given to the contributing researchers and their institutions for providing the data and methods summarized here. report
Note that the environment department provides no direct contact details in this document. The study reference remains accessible through institutional publications that summarize methods and conclusions without including external links in this text. note